Bose-Einstein condensation of excitons in Cu2_2O

We present a parameter-free model which estimates the density of excitons in Cu$_2$O, related to experiments that have tried to create an excitonic Bose-Einstein condensate. Our study demonstrates that the triplet-state excitons move along adiabats and obey classical statistics, while the singlet-state excitons are a possible candidate for forming a Bose-Einstein condensate. Finally we show that the results of this study do not change qualitatively in a two-dimensional exciton gas, which can be realized in a quantum well.Comment: 6 pages, RevTex, 1 ps figur

Evidence that the mitochondrial leucyl tRNA synthetase (LARS2) gene represents a novel type 2 diabetes susceptibility gene

Previously, we have shown that a mutation in the mitochondrial DNA-encoded tRNA(Leu(UUR)) gene is associated with type 2 diabetes. One of the consequences of this mutation is a reduced aminoacylation of tRNA(Leu(UUR)). In this study, we have examined whether variants in the leucyl tRNA synthetase gene (LARS2), involved in aminoacylation of tRNA(Leu(UUR)), associate with type 2 diabetes. Direct sequencing of LARS2 cDNA from 25 type 2 diabetic subjects revealed eight single nucleotide polymorphisms. Two of the variants were examined in 7,836 subjects from four independent populations in the Netherlands and Denmark. A -109 g/a variant was not associated with type 2 diabetes. Allele frequencies for the other variant, H324Q, were 3.5% in type 2 diabetic and 2.7% in control subjects, respectively. The common odds ratio across all four studies was 1.40 (95% CI 1.12-1.76), P = 0.004. There were no significant differences in clinical variables between carriers and noncarriers. In this study, we provide evidence that the LARS2 gene may represent a novel type 2 diabetes susceptibility gene. The mechanism by which the H324Q variant enhances type 2 diabetes risk needs to be further established. This is the first report of association between an aminoacyl tRNA synthetase gene and disease. Our results further highlight the important role of mitochondria in glucose homeostasis

Reporting Helicopter Emergency Medical Services in Major Incidents: A Delphi Study

Peer reviewe

Aneurysmal disease is associated with lower carotid intima-media thickness than occlusive arterial disease

Objective: Patients with aneurysmal and occlusive arterial disease have overlapping cardiovascular risk profiles. The question remains how atherosclerosis is related to the formation of aortic aneurysms. Common carotid artery intima-media thickness (CIMT) is an easily accessible and objective marker of early atherosclerosis. The aim of the current study was to investigate whether there is a difference in atherosclerotic burden as measured by CIMT between patients with aneurysmal and those with occlusive arterial disease. Methods: From 2004 to 2011, the CIMT was measured using B-mode ultrasound scanning in patients undergoing vascular surgery for aortic aneurysmal or occlusive arterial disease at the Erasmus University Medical Center. Cardiovascular risk factors, comorbidities, and medication were recorded. Patients treated for combined aneurysmal and occlusive arterial disease and patients diagnosed with a genetic aneurysm syndrome were excluded. Univariable and multivariable analyses wer

Cardiovascular safety of celecoxib in acute myocardial infarction patients: a nested case-control study

The objective was to measure the impact of exposure to coxibs and non-steroidal antiinflammatory drugs (NSAID) on morbidity and mortality in older patients with acute myocardial infarction (AMI). A nested case-control study was carried out using an exhaustive population-based cohort of patients aged 66 years and older living in Quebec (Canada) who survived a hospitalization for AMI (ICD-9 410) between 1999 and 2002. The main variables were all-cause and cardiovascular (CV) death, subsequent hospital admission for AMI, and a composite end-point including recurrent AMI or CV death. Conditional logistic regressions were used to estimate the risk of mortality and morbidity. A total of 19,823 patients aged 66 years and older survived hospitalization for AMI in the province of Quebec between 1999 and 2002. After controlling for covariables, the risk of subsequent AMI and the risk of composite end-point were increased by the use of rofecoxib. The risk of subsequent AMI was particularly high for new rofecoxib users (HR 2.47, 95% CI 1.57–3.89). No increased risk was observed for celecoxib users. No increased risk of CV death was observed for patients exposed to coxibs or NSAIDs. Patients newly exposed to NSAIDs were at an increased risk of death (HR 2.22, 95% CI 1.30–3.77) and of composite end-point (HR 2.28, 95% CI 1.35–3.84). Users of rofecoxib and NSAIDs, but not celecoxib, were at an increased risk of recurrent AMI and of composite end-point. Surprisingly, no increased risk of CV death was observed. Further studies are needed to better understand these apparently contradictory results

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at $\lg(E/{\rm eV})=18.5-19.0$ differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass $A > 4$. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

The micromorphology of glaciolacustrine varve sediments and their use for reconstructing palaeoglaciological and palaeoenvironmental change

Former glaciolacustrine systems are an important archive of palaeoglaciological, palaeoenvironmental and palaeoclimatic change. The annually laminated (varved) sediments that, under certain conditions, accumulate in former glacial lakes, offer a rare opportunity to reconstruct such changes (e.g. glacier advance and retreat cycles, glacier ablation trends, permafrost melt, nival events) at annual or even sub-annual temporal resolution. Data of this kind are desirable for their ability to guide and test numerical model simulations of glacier dynamics and palaeoclimatic change that occur over rapid time intervals, with implications for predicting future glacier response to climatic change, or the effects of weather and climate events on lake sedimentation. The most valuable records preserved in glaciolacustrine systems are continuous varved sequences formed in the distal parts of glacial lakes, where microscale lamination structures can accumulate relatively undisturbed. Technological advances, in the last few decades, have enabled improved characterisation of glaciolacustrine varve microfacies and the precise measurement of varve thickness at the micrometre scale. However, unlike in cognate fields (e.g. soil science), protocols for the robust and consistent description and interpretation of glaciolacustrine varve sediments are lacking. To fill this gap, and to provide a resource for future studies of glaciolacustrine varved sediments, this paper reviews the processes of sedimentation in glacial lake basins, and presents the defining microfacies characteristics of glacial varves using a descriptive protocol that uses consistent examination of grain size, sorting, structure, nature of contacts, development of plasmic fabrics and features such as dropgrains and intraclasts within individual laminations. These lamination types are then combined into lamination sets, whose structures can be interpreted as glaciolacustrine varves. Within this framework, we define five principal assemblages of glaciolacustrine varve microfacies which, if clearly identified in palaeoglaciolacustrine settings, enable more detailed palaeoenvironmental interpretations to be made. Finally, we discuss the utility and complexities of reconstructing the evolution of former glacial lake systems using varve microfacies and thickness datasets